Filtering QCanBusDevice messages

[tanselgonul]

I am trying to filter the received can frames according to frameId and frameIdMask but Pyside6 source file doesn't seem to have the class attributes I am looking for. I couldn't find a Python documentation about filtering but C++ implementation has the class Filter with the member variables like this

    struct Filter
    {
        friend constexpr bool operator==(const Filter &a, const Filter &b) noexcept
        {
            return a.frameId == b.frameId && a.frameIdMask == b.frameIdMask
                    && a.type == b.type && a.format == b.format;
        }

        friend constexpr bool operator!=(const Filter &a, const Filter &b) noexcept
        {
            return !operator==(a, b);
        }

        enum FormatFilter {
            MatchBaseFormat = 0x0001,
            MatchExtendedFormat = 0x0002,
            MatchBaseAndExtendedFormat = 0x0003,
        };
        Q_DECLARE_FLAGS(FormatFilters, FormatFilter)

        QCanBusFrame::FrameId frameId = 0;
        QCanBusFrame::FrameId frameIdMask = 0;
        QCanBusFrame::FrameType type = QCanBusFrame::InvalidFrame;
        FormatFilter format = MatchBaseAndExtendedFormat;
    };

And the given usage example is like this

QCanBusDevice::Filter filter;
QList<QCanBusDevice::Filter> filterList;

// filter all CAN bus packages with id 0x444 (base) or 0xXXXXX444 (extended)
filter.frameId = 0x444u;
filter.frameIdMask = 0x7FFu;
filter.format = QCanBusDevice::Filter::MatchBaseAndExtendedFormat;
filter.type = QCanBusFrame::InvalidFrame;
filterList.append(filter);

// apply filter
device->setConfigurationParameter(QCanBusDevice::RawFilterKey, QVariant::fromValue(filterList));

But on the python side of things I couldn't figure out how to construct the Filter object since class Filter declaration only includes this

    class Filter(Shiboken.Object):

        class FormatFilter(enum.Flag):

            MatchBaseFormat          : QCanBusDevice.Filter.FormatFilter = ... # 0x1
            MatchExtendedFormat      : QCanBusDevice.Filter.FormatFilter = ... # 0x2
            MatchBaseAndExtendedFormat: QCanBusDevice.Filter.FormatFilter = ... # 0x3


        @overload
        def __init__(self) -> None: ...
        @overload
        def __init__(self, Filter: PySide6.QtSerialBus.QCanBusDevice.Filter) -> None: ...

        @staticmethod
        def __copy__() -> None: ...

[SGaist]

Hi and welcome to devnet,

I currently don't know if it's the correct solution but intuitively, I would go with implementing the __ne__ and __eq__ methods in your filter class.

[friedemannkleint]

Reimplementing operator eq will not work since this is not a base class. But the filter fields can be set like in C++, for example:

import sys
from PySide6.QtCore import QCoreApplication, QLibraryInfo, qVersion, Qt
from PySide6.QtSerialBus import QCanBusDevice, QCanBus

if __name__ == '__main__':
    app = QCoreApplication(sys.argv)
    device, name = QCanBus.instance().createDevice("passthrucan", "test")
    print(device, name)
    filters = []
    flt = QCanBusDevice.Filter()
    print("flt.format=", flt.format, "flt.type=", flt.type)
    print("flt.frameId=", flt.frameId, "flt.frameIdMask=", flt.frameIdMask )
    flt.format = QCanBusDevice.Filter.FormatFilter.MatchBaseFormat
    filters.append(flt)
    flt = QCanBusDevice.Filter()
    flt.format = QCanBusDevice.Filter.FormatFilter.MatchBaseAndExtendedFormat
    filters.append(flt)
    print("Setting: ", flt)
    device.setConfigurationParameter(QCanBusDevice.ConfigurationKey.RawFilterKey, filters)
    ret = device.configurationParameter(QCanBusDevice.ConfigurationKey.RawFilterKey)
    print("ret=", ret)

produces

<PySide6.QtSerialBus.QCanBusDevice(0x11c31f0) at 0x7050c09d0e40>
flt.format= FormatFilter.MatchBaseAndExtendedFormat flt.type= FrameType.InvalidFrame
flt.frameId= 0 flt.frameIdMask= 0
Setting:  <PySide6.QtSerialBus.QCanBusDevice.Filter object at 0x7050c09d0ec0>
ret= [<PySide6.QtSerialBus.QCanBusDevice.Filter object at 0x7050c09d2540>, <PySide6.QtSerialBus.QCanBusDevice.Filter object at 0x7050c09d3880>]

[SGaist]

@friedemannkleint Nice !

It might be worth adding something about it in the python part of the doc.